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linux-zen-desktop/arch/powerpc/platforms/pseries/vas.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2020-21 IBM Corp.
*/
#define pr_fmt(fmt) "vas: " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <asm/machdep.h>
#include <asm/hvcall.h>
#include <asm/plpar_wrappers.h>
#include <asm/firmware.h>
#include <asm/vas.h>
#include "vas.h"
#define VAS_INVALID_WIN_ADDRESS 0xFFFFFFFFFFFFFFFFul
#define VAS_DEFAULT_DOMAIN_ID 0xFFFFFFFFFFFFFFFFul
/* The hypervisor allows one credit per window right now */
#define DEF_WIN_CREDS 1
static struct vas_all_caps caps_all;
static bool copypaste_feat;
static struct hv_vas_cop_feat_caps hv_cop_caps;
static struct vas_caps vascaps[VAS_MAX_FEAT_TYPE];
static DEFINE_MUTEX(vas_pseries_mutex);
static bool migration_in_progress;
static long hcall_return_busy_check(long rc)
{
/* Check if we are stalled for some time */
if (H_IS_LONG_BUSY(rc)) {
msleep(get_longbusy_msecs(rc));
rc = H_BUSY;
} else if (rc == H_BUSY) {
cond_resched();
}
return rc;
}
/*
* Allocate VAS window hcall
*/
static int h_allocate_vas_window(struct pseries_vas_window *win, u64 *domain,
u8 wintype, u16 credits)
{
long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
long rc;
do {
rc = plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, wintype,
credits, domain[0], domain[1], domain[2],
domain[3], domain[4], domain[5]);
rc = hcall_return_busy_check(rc);
} while (rc == H_BUSY);
if (rc == H_SUCCESS) {
if (win->win_addr == VAS_INVALID_WIN_ADDRESS) {
pr_err("H_ALLOCATE_VAS_WINDOW: COPY/PASTE is not supported\n");
return -ENOTSUPP;
}
win->vas_win.winid = retbuf[0];
win->win_addr = retbuf[1];
win->complete_irq = retbuf[2];
win->fault_irq = retbuf[3];
return 0;
}
pr_err("H_ALLOCATE_VAS_WINDOW error: %ld, wintype: %u, credits: %u\n",
rc, wintype, credits);
return -EIO;
}
/*
* Deallocate VAS window hcall.
*/
static int h_deallocate_vas_window(u64 winid)
{
long rc;
do {
rc = plpar_hcall_norets(H_DEALLOCATE_VAS_WINDOW, winid);
rc = hcall_return_busy_check(rc);
} while (rc == H_BUSY);
if (rc == H_SUCCESS)
return 0;
pr_err("H_DEALLOCATE_VAS_WINDOW error: %ld, winid: %llu\n",
rc, winid);
return -EIO;
}
/*
* Modify VAS window.
* After the window is opened with allocate window hcall, configure it
* with flags and LPAR PID before using.
*/
static int h_modify_vas_window(struct pseries_vas_window *win)
{
long rc;
/*
* AMR value is not supported in Linux VAS implementation.
* The hypervisor ignores it if 0 is passed.
*/
do {
rc = plpar_hcall_norets(H_MODIFY_VAS_WINDOW,
win->vas_win.winid, win->pid, 0,
VAS_MOD_WIN_FLAGS, 0);
rc = hcall_return_busy_check(rc);
} while (rc == H_BUSY);
if (rc == H_SUCCESS)
return 0;
pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u pid %u\n",
rc, win->vas_win.winid, win->pid);
return -EIO;
}
/*
* This hcall is used to determine the capabilities from the hypervisor.
* @hcall: H_QUERY_VAS_CAPABILITIES or H_QUERY_NX_CAPABILITIES
* @query_type: If 0 is passed, the hypervisor returns the overall
* capabilities which provides all feature(s) that are
* available. Then query the hypervisor to get the
* corresponding capabilities for the specific feature.
* Example: H_QUERY_VAS_CAPABILITIES provides VAS GZIP QoS
* and VAS GZIP Default capabilities.
* H_QUERY_NX_CAPABILITIES provides NX GZIP
* capabilities.
* @result: Return buffer to save capabilities.
*/
int h_query_vas_capabilities(const u64 hcall, u8 query_type, u64 result)
{
long rc;
rc = plpar_hcall_norets(hcall, query_type, result);
if (rc == H_SUCCESS)
return 0;
/* H_FUNCTION means HV does not support VAS so don't print an error */
if (rc != H_FUNCTION) {
pr_err("%s error %ld, query_type %u, result buffer 0x%llx\n",
(hcall == H_QUERY_VAS_CAPABILITIES) ?
"H_QUERY_VAS_CAPABILITIES" :
"H_QUERY_NX_CAPABILITIES",
rc, query_type, result);
}
return -EIO;
}
EXPORT_SYMBOL_GPL(h_query_vas_capabilities);
/*
* hcall to get fault CRB from the hypervisor.
*/
static int h_get_nx_fault(u32 winid, u64 buffer)
{
long rc;
rc = plpar_hcall_norets(H_GET_NX_FAULT, winid, buffer);
if (rc == H_SUCCESS)
return 0;
pr_err("H_GET_NX_FAULT error: %ld, winid %u, buffer 0x%llx\n",
rc, winid, buffer);
return -EIO;
}
/*
* Handle the fault interrupt.
* When the fault interrupt is received for each window, query the
* hypervisor to get the fault CRB on the specific fault. Then
* process the CRB by updating CSB or send signal if the user space
* CSB is invalid.
* Note: The hypervisor forwards an interrupt for each fault request.
* So one fault CRB to process for each H_GET_NX_FAULT hcall.
*/
static irqreturn_t pseries_vas_fault_thread_fn(int irq, void *data)
{
struct pseries_vas_window *txwin = data;
struct coprocessor_request_block crb;
struct vas_user_win_ref *tsk_ref;
int rc;
while (atomic_read(&txwin->pending_faults)) {
rc = h_get_nx_fault(txwin->vas_win.winid, (u64)virt_to_phys(&crb));
if (!rc) {
tsk_ref = &txwin->vas_win.task_ref;
vas_dump_crb(&crb);
vas_update_csb(&crb, tsk_ref);
}
atomic_dec(&txwin->pending_faults);
}
return IRQ_HANDLED;
}
/*
* irq_default_primary_handler() can be used only with IRQF_ONESHOT
* which disables IRQ before executing the thread handler and enables
* it after. But this disabling interrupt sets the VAS IRQ OFF
* state in the hypervisor. If the NX generates fault interrupt
* during this window, the hypervisor will not deliver this
* interrupt to the LPAR. So use VAS specific IRQ handler instead
* of calling the default primary handler.
*/
static irqreturn_t pseries_vas_irq_handler(int irq, void *data)
{
struct pseries_vas_window *txwin = data;
/*
* The thread hanlder will process this interrupt if it is
* already running.
*/
atomic_inc(&txwin->pending_faults);
return IRQ_WAKE_THREAD;
}
/*
* Allocate window and setup IRQ mapping.
*/
static int allocate_setup_window(struct pseries_vas_window *txwin,
u64 *domain, u8 wintype)
{
int rc;
rc = h_allocate_vas_window(txwin, domain, wintype, DEF_WIN_CREDS);
if (rc)
return rc;
/*
* On PowerVM, the hypervisor setup and forwards the fault
* interrupt per window. So the IRQ setup and fault handling
* will be done for each open window separately.
*/
txwin->fault_virq = irq_create_mapping(NULL, txwin->fault_irq);
if (!txwin->fault_virq) {
pr_err("Failed irq mapping %d\n", txwin->fault_irq);
rc = -EINVAL;
goto out_win;
}
txwin->name = kasprintf(GFP_KERNEL, "vas-win-%d",
txwin->vas_win.winid);
if (!txwin->name) {
rc = -ENOMEM;
goto out_irq;
}
rc = request_threaded_irq(txwin->fault_virq,
pseries_vas_irq_handler,
pseries_vas_fault_thread_fn, 0,
txwin->name, txwin);
if (rc) {
pr_err("VAS-Window[%d]: Request IRQ(%u) failed with %d\n",
txwin->vas_win.winid, txwin->fault_virq, rc);
goto out_free;
}
txwin->vas_win.wcreds_max = DEF_WIN_CREDS;
return 0;
out_free:
kfree(txwin->name);
out_irq:
irq_dispose_mapping(txwin->fault_virq);
out_win:
h_deallocate_vas_window(txwin->vas_win.winid);
return rc;
}
static inline void free_irq_setup(struct pseries_vas_window *txwin)
{
free_irq(txwin->fault_virq, txwin);
kfree(txwin->name);
irq_dispose_mapping(txwin->fault_virq);
}
static struct vas_window *vas_allocate_window(int vas_id, u64 flags,
enum vas_cop_type cop_type)
{
long domain[PLPAR_HCALL9_BUFSIZE] = {VAS_DEFAULT_DOMAIN_ID};
struct vas_cop_feat_caps *cop_feat_caps;
struct vas_caps *caps;
struct pseries_vas_window *txwin;
int rc;
txwin = kzalloc(sizeof(*txwin), GFP_KERNEL);
if (!txwin)
return ERR_PTR(-ENOMEM);
/*
* A VAS window can have many credits which means that many
* requests can be issued simultaneously. But the hypervisor
* restricts one credit per window.
* The hypervisor introduces 2 different types of credits:
* Default credit type (Uses normal priority FIFO):
* A limited number of credits are assigned to partitions
* based on processor entitlement. But these credits may be
* over-committed on a system depends on whether the CPUs
* are in shared or dedicated modes - that is, more requests
* may be issued across the system than NX can service at
* once which can result in paste command failure (RMA_busy).
* Then the process has to resend requests or fall-back to
* SW compression.
* Quality of Service (QoS) credit type (Uses high priority FIFO):
* To avoid NX HW contention, the system admins can assign
* QoS credits for each LPAR so that this partition is
* guaranteed access to NX resources. These credits are
* assigned to partitions via the HMC.
* Refer PAPR for more information.
*
* Allocate window with QoS credits if user requested. Otherwise
* default credits are used.
*/
if (flags & VAS_TX_WIN_FLAG_QOS_CREDIT)
caps = &vascaps[VAS_GZIP_QOS_FEAT_TYPE];
else
caps = &vascaps[VAS_GZIP_DEF_FEAT_TYPE];
cop_feat_caps = &caps->caps;
if (atomic_inc_return(&cop_feat_caps->nr_used_credits) >
atomic_read(&cop_feat_caps->nr_total_credits)) {
pr_err("Credits are not available to allocate window\n");
rc = -EINVAL;
goto out;
}
if (vas_id == -1) {
/*
* The user space is requesting to allocate a window on
* a VAS instance where the process is executing.
* On PowerVM, domain values are passed to the hypervisor
* to select VAS instance. Useful if the process is
* affinity to NUMA node.
* The hypervisor selects VAS instance if
* VAS_DEFAULT_DOMAIN_ID (-1) is passed for domain values.
* The h_allocate_vas_window hcall is defined to take a
* domain values as specified by h_home_node_associativity,
* So no unpacking needs to be done.
*/
rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, domain,
VPHN_FLAG_VCPU, hard_smp_processor_id());
if (rc != H_SUCCESS) {
pr_err("H_HOME_NODE_ASSOCIATIVITY error: %d\n", rc);
goto out;
}
}
txwin->pid = mfspr(SPRN_PID);
/*
* Allocate / Deallocate window hcalls and setup / free IRQs
* have to be protected with mutex.
* Open VAS window: Allocate window hcall and setup IRQ
* Close VAS window: Deallocate window hcall and free IRQ
* The hypervisor waits until all NX requests are
* completed before closing the window. So expects OS
* to handle NX faults, means IRQ can be freed only
* after the deallocate window hcall is returned.
* So once the window is closed with deallocate hcall before
* the IRQ is freed, it can be assigned to new allocate
* hcall with the same fault IRQ by the hypervisor. It can
* result in setup IRQ fail for the new window since the
* same fault IRQ is not freed by the OS before.
*/
mutex_lock(&vas_pseries_mutex);
if (migration_in_progress)
rc = -EBUSY;
else
rc = allocate_setup_window(txwin, (u64 *)&domain[0],
cop_feat_caps->win_type);
mutex_unlock(&vas_pseries_mutex);
if (rc)
goto out;
/*
* Modify window and it is ready to use.
*/
rc = h_modify_vas_window(txwin);
if (!rc)
rc = get_vas_user_win_ref(&txwin->vas_win.task_ref);
if (rc)
goto out_free;
txwin->win_type = cop_feat_caps->win_type;
mutex_lock(&vas_pseries_mutex);
/*
* Possible to lose the acquired credit with DLPAR core
* removal after the window is opened. So if there are any
* closed windows (means with lost credits), do not give new
* window to user space. New windows will be opened only
* after the existing windows are reopened when credits are
* available.
*/
if (!caps->nr_close_wins) {
list_add(&txwin->win_list, &caps->list);
caps->nr_open_windows++;
mutex_unlock(&vas_pseries_mutex);
vas_user_win_add_mm_context(&txwin->vas_win.task_ref);
return &txwin->vas_win;
}
mutex_unlock(&vas_pseries_mutex);
put_vas_user_win_ref(&txwin->vas_win.task_ref);
rc = -EBUSY;
pr_err("No credit is available to allocate window\n");
out_free:
/*
* Window is not operational. Free IRQ before closing
* window so that do not have to hold mutex.
*/
free_irq_setup(txwin);
h_deallocate_vas_window(txwin->vas_win.winid);
out:
atomic_dec(&cop_feat_caps->nr_used_credits);
kfree(txwin);
return ERR_PTR(rc);
}
static u64 vas_paste_address(struct vas_window *vwin)
{
struct pseries_vas_window *win;
win = container_of(vwin, struct pseries_vas_window, vas_win);
return win->win_addr;
}
static int deallocate_free_window(struct pseries_vas_window *win)
{
int rc = 0;
/*
* The hypervisor waits for all requests including faults
* are processed before closing the window - Means all
* credits have to be returned. In the case of fault
* request, a credit is returned after OS issues
* H_GET_NX_FAULT hcall.
* So free IRQ after executing H_DEALLOCATE_VAS_WINDOW
* hcall.
*/
rc = h_deallocate_vas_window(win->vas_win.winid);
if (!rc)
free_irq_setup(win);
return rc;
}
static int vas_deallocate_window(struct vas_window *vwin)
{
struct pseries_vas_window *win;
struct vas_cop_feat_caps *caps;
int rc = 0;
if (!vwin)
return -EINVAL;
win = container_of(vwin, struct pseries_vas_window, vas_win);
/* Should not happen */
if (win->win_type >= VAS_MAX_FEAT_TYPE) {
pr_err("Window (%u): Invalid window type %u\n",
vwin->winid, win->win_type);
return -EINVAL;
}
caps = &vascaps[win->win_type].caps;
mutex_lock(&vas_pseries_mutex);
/*
* VAS window is already closed in the hypervisor when
* lost the credit or with migration. So just remove the entry
* from the list, remove task references and free vas_window
* struct.
*/
if (!(win->vas_win.status & VAS_WIN_NO_CRED_CLOSE) &&
!(win->vas_win.status & VAS_WIN_MIGRATE_CLOSE)) {
rc = deallocate_free_window(win);
if (rc) {
mutex_unlock(&vas_pseries_mutex);
return rc;
}
} else
vascaps[win->win_type].nr_close_wins--;
list_del(&win->win_list);
atomic_dec(&caps->nr_used_credits);
vascaps[win->win_type].nr_open_windows--;
mutex_unlock(&vas_pseries_mutex);
mm_context_remove_vas_window(vwin->task_ref.mm);
put_vas_user_win_ref(&vwin->task_ref);
kfree(win);
return 0;
}
static const struct vas_user_win_ops vops_pseries = {
.open_win = vas_allocate_window, /* Open and configure window */
.paste_addr = vas_paste_address, /* To do copy/paste */
.close_win = vas_deallocate_window, /* Close window */
};
/*
* Supporting only nx-gzip coprocessor type now, but this API code
* extended to other coprocessor types later.
*/
int vas_register_api_pseries(struct module *mod, enum vas_cop_type cop_type,
const char *name)
{
if (!copypaste_feat)
return -ENOTSUPP;
return vas_register_coproc_api(mod, cop_type, name, &vops_pseries);
}
EXPORT_SYMBOL_GPL(vas_register_api_pseries);
void vas_unregister_api_pseries(void)
{
vas_unregister_coproc_api();
}
EXPORT_SYMBOL_GPL(vas_unregister_api_pseries);
/*
* Get the specific capabilities based on the feature type.
* Right now supports GZIP default and GZIP QoS capabilities.
*/
static int __init get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
struct hv_vas_cop_feat_caps *hv_caps)
{
struct vas_cop_feat_caps *caps;
struct vas_caps *vcaps;
int rc = 0;
vcaps = &vascaps[type];
memset(vcaps, 0, sizeof(*vcaps));
INIT_LIST_HEAD(&vcaps->list);
vcaps->feat = feat;
caps = &vcaps->caps;
rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, feat,
(u64)virt_to_phys(hv_caps));
if (rc)
return rc;
caps->user_mode = hv_caps->user_mode;
if (!(caps->user_mode & VAS_COPY_PASTE_USER_MODE)) {
pr_err("User space COPY/PASTE is not supported\n");
return -ENOTSUPP;
}
caps->descriptor = be64_to_cpu(hv_caps->descriptor);
caps->win_type = hv_caps->win_type;
if (caps->win_type >= VAS_MAX_FEAT_TYPE) {
pr_err("Unsupported window type %u\n", caps->win_type);
return -EINVAL;
}
caps->max_lpar_creds = be16_to_cpu(hv_caps->max_lpar_creds);
caps->max_win_creds = be16_to_cpu(hv_caps->max_win_creds);
atomic_set(&caps->nr_total_credits,
be16_to_cpu(hv_caps->target_lpar_creds));
if (feat == VAS_GZIP_DEF_FEAT) {
caps->def_lpar_creds = be16_to_cpu(hv_caps->def_lpar_creds);
if (caps->max_win_creds < DEF_WIN_CREDS) {
pr_err("Window creds(%u) > max allowed window creds(%u)\n",
DEF_WIN_CREDS, caps->max_win_creds);
return -EINVAL;
}
}
rc = sysfs_add_vas_caps(caps);
if (rc)
return rc;
copypaste_feat = true;
return 0;
}
/*
* VAS windows can be closed due to lost credits when the core is
* removed. So reopen them if credits are available due to DLPAR
* core add and set the window active status. When NX sees the page
* fault on the unmapped paste address, the kernel handles the fault
* by setting the remapping to new paste address if the window is
* active.
*/
static int reconfig_open_windows(struct vas_caps *vcaps, int creds,
bool migrate)
{
long domain[PLPAR_HCALL9_BUFSIZE] = {VAS_DEFAULT_DOMAIN_ID};
struct vas_cop_feat_caps *caps = &vcaps->caps;
struct pseries_vas_window *win = NULL, *tmp;
int rc, mv_ents = 0;
int flag;
/*
* Nothing to do if there are no closed windows.
*/
if (!vcaps->nr_close_wins)
return 0;
/*
* For the core removal, the hypervisor reduces the credits
* assigned to the LPAR and the kernel closes VAS windows
* in the hypervisor depends on reduced credits. The kernel
* uses LIFO (the last windows that are opened will be closed
* first) and expects to open in the same order when credits
* are available.
* For example, 40 windows are closed when the LPAR lost 2 cores
* (dedicated). If 1 core is added, this LPAR can have 20 more
* credits. It means the kernel can reopen 20 windows. So move
* 20 entries in the VAS windows lost and reopen next 20 windows.
* For partition migration, reopen all windows that are closed
* during resume.
*/
if ((vcaps->nr_close_wins > creds) && !migrate)
mv_ents = vcaps->nr_close_wins - creds;
list_for_each_entry_safe(win, tmp, &vcaps->list, win_list) {
if (!mv_ents)
break;
mv_ents--;
}
/*
* Open windows if they are closed only with migration or
* DLPAR (lost credit) before.
*/
if (migrate)
flag = VAS_WIN_MIGRATE_CLOSE;
else
flag = VAS_WIN_NO_CRED_CLOSE;
list_for_each_entry_safe_from(win, tmp, &vcaps->list, win_list) {
/*
* This window is closed with DLPAR and migration events.
* So reopen the window with the last event.
* The user space is not suspended with the current
* migration notifier. So the user space can issue DLPAR
* CPU hotplug while migration in progress. In this case
* this window will be opened with the last event.
*/
if ((win->vas_win.status & VAS_WIN_NO_CRED_CLOSE) &&
(win->vas_win.status & VAS_WIN_MIGRATE_CLOSE)) {
win->vas_win.status &= ~flag;
continue;
}
/*
* Nothing to do on this window if it is not closed
* with this flag
*/
if (!(win->vas_win.status & flag))
continue;
rc = allocate_setup_window(win, (u64 *)&domain[0],
caps->win_type);
if (rc)
return rc;
rc = h_modify_vas_window(win);
if (rc)
goto out;
mutex_lock(&win->vas_win.task_ref.mmap_mutex);
/*
* Set window status to active
*/
win->vas_win.status &= ~flag;
mutex_unlock(&win->vas_win.task_ref.mmap_mutex);
win->win_type = caps->win_type;
if (!--vcaps->nr_close_wins)
break;
}
return 0;
out:
/*
* Window modify HCALL failed. So close the window to the
* hypervisor and return.
*/
free_irq_setup(win);
h_deallocate_vas_window(win->vas_win.winid);
return rc;
}
/*
* The hypervisor reduces the available credits if the LPAR lost core. It
* means the excessive windows should not be active and the user space
* should not be using these windows to send compression requests to NX.
* So the kernel closes the excessive windows and unmap the paste address
* such that the user space receives paste instruction failure. Then up to
* the user space to fall back to SW compression and manage with the
* existing windows.
*/
static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
bool migrate)
{
struct pseries_vas_window *win, *tmp;
struct vas_user_win_ref *task_ref;
struct vm_area_struct *vma;
int rc = 0, flag;
if (migrate)
flag = VAS_WIN_MIGRATE_CLOSE;
else
flag = VAS_WIN_NO_CRED_CLOSE;
list_for_each_entry_safe(win, tmp, &vcap->list, win_list) {
/*
* This window is already closed due to lost credit
* or for migration before. Go for next window.
* For migration, nothing to do since this window
* closed for DLPAR and will be reopened even on
* the destination system with other DLPAR operation.
*/
if ((win->vas_win.status & VAS_WIN_MIGRATE_CLOSE) ||
(win->vas_win.status & VAS_WIN_NO_CRED_CLOSE)) {
win->vas_win.status |= flag;
continue;
}
task_ref = &win->vas_win.task_ref;
/*
* VAS mmap (coproc_mmap()) and its fault handler
* (vas_mmap_fault()) are called after holding mmap lock.
* So hold mmap mutex after mmap_lock to avoid deadlock.
*/
mmap_write_lock(task_ref->mm);
mutex_lock(&task_ref->mmap_mutex);
vma = task_ref->vma;
/*
* Number of available credits are reduced, So select
* and close windows.
*/
win->vas_win.status |= flag;
/*
* vma is set in the original mapping. But this mapping
* is done with mmap() after the window is opened with ioctl.
* so we may not see the original mapping if the core remove
* is done before the original mmap() and after the ioctl.
*/
if (vma)
zap_vma_pages(vma);
mutex_unlock(&task_ref->mmap_mutex);
mmap_write_unlock(task_ref->mm);
/*
* Close VAS window in the hypervisor, but do not
* free vas_window struct since it may be reused
* when the credit is available later (DLPAR with
* adding cores). This struct will be used
* later when the process issued with close(FD).
*/
rc = deallocate_free_window(win);
/*
* This failure is from the hypervisor.
* No way to stop migration for these failures.
* So ignore error and continue closing other windows.
*/
if (rc && !migrate)
return rc;
vcap->nr_close_wins++;
/*
* For migration, do not depend on lpar_creds in case if
* mismatch with the hypervisor value (should not happen).
* So close all active windows in the list and will be
* reopened windows based on the new lpar_creds on the
* destination system during resume.
*/
if (!migrate && !--excess_creds)
break;
}
return 0;
}
/*
* Get new VAS capabilities when the core add/removal configuration
* changes. Reconfig window configurations based on the credits
* availability from this new capabilities.
*/
int vas_reconfig_capabilties(u8 type, int new_nr_creds)
{
struct vas_cop_feat_caps *caps;
int old_nr_creds;
struct vas_caps *vcaps;
int rc = 0, nr_active_wins;
if (type >= VAS_MAX_FEAT_TYPE) {
pr_err("Invalid credit type %d\n", type);
return -EINVAL;
}
vcaps = &vascaps[type];
caps = &vcaps->caps;
mutex_lock(&vas_pseries_mutex);
old_nr_creds = atomic_read(&caps->nr_total_credits);
atomic_set(&caps->nr_total_credits, new_nr_creds);
/*
* The total number of available credits may be decreased or
* increased with DLPAR operation. Means some windows have to be
* closed / reopened. Hold the vas_pseries_mutex so that the
* user space can not open new windows.
*/
if (old_nr_creds < new_nr_creds) {
/*
* If the existing target credits is less than the new
* target, reopen windows if they are closed due to
* the previous DLPAR (core removal).
*/
rc = reconfig_open_windows(vcaps, new_nr_creds - old_nr_creds,
false);
} else {
/*
* # active windows is more than new LPAR available
* credits. So close the excessive windows.
* On pseries, each window will have 1 credit.
*/
nr_active_wins = vcaps->nr_open_windows - vcaps->nr_close_wins;
if (nr_active_wins > new_nr_creds)
rc = reconfig_close_windows(vcaps,
nr_active_wins - new_nr_creds,
false);
}
mutex_unlock(&vas_pseries_mutex);
return rc;
}
int pseries_vas_dlpar_cpu(void)
{
int new_nr_creds, rc;
/*
* NX-GZIP is not enabled. Nothing to do for DLPAR event
*/
if (!copypaste_feat)
return 0;
rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES,
vascaps[VAS_GZIP_DEF_FEAT_TYPE].feat,
(u64)virt_to_phys(&hv_cop_caps));
if (!rc) {
new_nr_creds = be16_to_cpu(hv_cop_caps.target_lpar_creds);
rc = vas_reconfig_capabilties(VAS_GZIP_DEF_FEAT_TYPE, new_nr_creds);
}
if (rc)
pr_err("Failed reconfig VAS capabilities with DLPAR\n");
return rc;
}
/*
* Total number of default credits available (target_credits)
* in LPAR depends on number of cores configured. It varies based on
* whether processors are in shared mode or dedicated mode.
* Get the notifier when CPU configuration is changed with DLPAR
* operation so that get the new target_credits (vas default capabilities)
* and then update the existing windows usage if needed.
*/
static int pseries_vas_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
struct of_reconfig_data *rd = data;
struct device_node *dn = rd->dn;
const __be32 *intserv = NULL;
int len;
/*
* For shared CPU partition, the hypervisor assigns total credits
* based on entitled core capacity. So updating VAS windows will
* be called from lparcfg_write().
*/
if (is_shared_processor())
return NOTIFY_OK;
if ((action == OF_RECONFIG_ATTACH_NODE) ||
(action == OF_RECONFIG_DETACH_NODE))
intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s",
&len);
/*
* Processor config is not changed
*/
if (!intserv)
return NOTIFY_OK;
return pseries_vas_dlpar_cpu();
}
static struct notifier_block pseries_vas_nb = {
.notifier_call = pseries_vas_notifier,
};
/*
* For LPM, all windows have to be closed on the source partition
* before migration and reopen them on the destination partition
* after migration. So closing windows during suspend and
* reopen them during resume.
*/
int vas_migration_handler(int action)
{
struct vas_cop_feat_caps *caps;
int old_nr_creds, new_nr_creds = 0;
struct vas_caps *vcaps;
int i, rc = 0;
/*
* NX-GZIP is not enabled. Nothing to do for migration.
*/
if (!copypaste_feat)
return rc;
mutex_lock(&vas_pseries_mutex);
if (action == VAS_SUSPEND)
migration_in_progress = true;
else
migration_in_progress = false;
for (i = 0; i < VAS_MAX_FEAT_TYPE; i++) {
vcaps = &vascaps[i];
caps = &vcaps->caps;
old_nr_creds = atomic_read(&caps->nr_total_credits);
rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES,
vcaps->feat,
(u64)virt_to_phys(&hv_cop_caps));
if (!rc) {
new_nr_creds = be16_to_cpu(hv_cop_caps.target_lpar_creds);
/*
* Should not happen. But incase print messages, close
* all windows in the list during suspend and reopen
* windows based on new lpar_creds on the destination
* system.
*/
if (old_nr_creds != new_nr_creds) {
pr_err("Target credits mismatch with the hypervisor\n");
pr_err("state(%d): lpar creds: %d HV lpar creds: %d\n",
action, old_nr_creds, new_nr_creds);
pr_err("Used creds: %d, Active creds: %d\n",
atomic_read(&caps->nr_used_credits),
vcaps->nr_open_windows - vcaps->nr_close_wins);
}
} else {
pr_err("state(%d): Get VAS capabilities failed with %d\n",
action, rc);
/*
* We can not stop migration with the current lpm
* implementation. So continue closing all windows in
* the list (during suspend) and return without
* opening windows (during resume) if VAS capabilities
* HCALL failed.
*/
if (action == VAS_RESUME)
goto out;
}
switch (action) {
case VAS_SUSPEND:
rc = reconfig_close_windows(vcaps, vcaps->nr_open_windows,
true);
break;
case VAS_RESUME:
atomic_set(&caps->nr_total_credits, new_nr_creds);
rc = reconfig_open_windows(vcaps, new_nr_creds, true);
break;
default:
/* should not happen */
pr_err("Invalid migration action %d\n", action);
rc = -EINVAL;
goto out;
}
/*
* Ignore errors during suspend and return for resume.
*/
if (rc && (action == VAS_RESUME))
goto out;
}
out:
mutex_unlock(&vas_pseries_mutex);
return rc;
}
static int __init pseries_vas_init(void)
{
struct hv_vas_all_caps *hv_caps;
int rc = 0;
/*
* Linux supports user space COPY/PASTE only with Radix
*/
if (!radix_enabled()) {
copypaste_feat = false;
pr_err("API is supported only with radix page tables\n");
return -ENOTSUPP;
}
hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
if (!hv_caps)
return -ENOMEM;
/*
* Get VAS overall capabilities by passing 0 to feature type.
*/
rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, 0,
(u64)virt_to_phys(hv_caps));
if (rc)
goto out;
caps_all.descriptor = be64_to_cpu(hv_caps->descriptor);
caps_all.feat_type = be64_to_cpu(hv_caps->feat_type);
sysfs_pseries_vas_init(&caps_all);
/*
* QOS capabilities available
*/
if (caps_all.feat_type & VAS_GZIP_QOS_FEAT_BIT) {
rc = get_vas_capabilities(VAS_GZIP_QOS_FEAT,
VAS_GZIP_QOS_FEAT_TYPE, &hv_cop_caps);
if (rc)
goto out;
}
/*
* Default capabilities available
*/
if (caps_all.feat_type & VAS_GZIP_DEF_FEAT_BIT)
rc = get_vas_capabilities(VAS_GZIP_DEF_FEAT,
VAS_GZIP_DEF_FEAT_TYPE, &hv_cop_caps);
if (!rc && copypaste_feat) {
if (firmware_has_feature(FW_FEATURE_LPAR))
of_reconfig_notifier_register(&pseries_vas_nb);
pr_info("GZIP feature is available\n");
} else {
/*
* Should not happen, but only when get default
* capabilities HCALL failed. So disable copy paste
* feature.
*/
copypaste_feat = false;
}
out:
kfree(hv_caps);
return rc;
}
machine_device_initcall(pseries, pseries_vas_init);
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